Book SummaryMere Christianity, by C. S. Lewis

1-Page Summary1-Page Book Summary of Mere Christianity

In Mere Christianity, C.S. Lewis sets out to explain and defend Christian beliefs to a skeptical modern audience through a series of essays—originally delivered as a series of radio addresses in the United Kingdom between 1941 and 1944. Broadcast to a population in the midst of World War II, Lewis's discussions on evil, forgiveness, and serving a greater good struck a chord with a wide audience.

C.S. Lewis was a professor of literature widely known for his children's fantasy series, The Chronicles of Narnia. He spent the first part of his adult life as an atheist before converting to Christianity in his early 30s, influenced by his close friendship with J.R.R. Tolkien, the Catholic author of The Lord of the Rings. Lewis wrote several books on Christianity and many Christians regard him as an important lay theologian.

In Mere Christianity, Lewis argues that Christianity is...

Mere Christianity Summary Part 1: Moral Laws and Their Creator

Lewis's first major argument for the credibility of Christianity is that morality is objective, universal, and non-material. Furthermore, he argues that these qualities provide evidence for the existence of a creator. To understand Lewis's argument, we'll take a closer look at his case for each of these claims in sequence.

Claim #1: Morality Is Objective and Universal

Lewis argues that morality is not something people invented, but, rather, is objective and universal—much like scientific claims about the material world. He pushes back against the idea that morals are something we decide for ourselves and are therefore malleable. Instead, he argues, morality is a fixed and universal truth, and we cannot simply declare what is right and wrong based on our own changing whims. He marshals two key pieces of evidence to support his perspective: Morality is objective because societies all have shared moral standards, and morality is universal because these standards remain remarkably consistent across cultures.

Moral Laws Are Objective

Lewis argues that morality is objective by pointing out that people quarrel by appealing to shared moral standards. For...

Mere Christianity Summary Part 2: The Christian Understanding of God

Lewis argues that objective, non-material morality supports not just the existence of a creator, but, specifically, a moral God who impels us to be good. This aligns with the Christian understanding of God’s moral nature. In this section, we'll explore the Christian understanding of God, how it differs from other theological beliefs, and why evil exists if the creator of the universe is good.

God Is on the Side of Good

Lewis argues that the moral laws point us to a Christian conception of a moral God who is on the side of good. Lewis makes this case with the following line of reasoning.

• The moral laws prefer good over evil.
• God created the moral laws.
• Therefore God too must prefer good over evil.

This leads us to a perception of a moral God, like the vision of God presented in Christian teachings. Lewis explores two theological perspectives that contradict this interpretation of God: pantheism and dualism. We'll define each below and explain Lewis's arguments against them.

Is God “Virtuous”?

While Lewis asserts that God is on the side of good, many Christian thinkers have stressed that this doesn’t mean that God is good in the same way that...

Mere Christianity Summary Part 3: Christian Virtues

God calls on everyone to choose good over evil, but how do we know what is “good”? Lewis argues that Christianity instructs us to be good by following Christian virtues, or moral principles that can be applied to a wide range of situations. This section will provide a brief overview of what those virtues are, as well as some of the benefits of choosing a virtuous life.

The Four Key Christian Virtues

Lewis explains that following God's moral law requires living your life according to four key Christian virtues: faith, benevolence, moderation, and humility.

Virtue #1: Faith

Lewis defines faith as a commitment to and trust in Christian teachings in the face of daily distractions and doubts. Lewis pushes back against the widely held idea that faith entails a blind or thoughtless belief in Christian doctrine. In fact, he writes that you should not believe in Christianity if you don’t think the evidence supports it.

Lewis also asserts that faith requires you to greet life with hope and optimism. To accept Christianity is to believe that there is something better in the next life and that the power of good is greater than the power of evil, both of which give...

Mere Christianity Summary Part 4: Answering God's Call to Virtue

Lewis argues that the creator calls on each of us to be virtuous. In this section, we'll explore Lewis's explanation of how you can answer this call. We’ll discuss Lewis’s conception of God's high moral standards and how you must surrender your will to pursue them. We’ll also cover Lewis’s beliefs about how this effort will change you and why your intentions matter.

God Holds You to a High Moral Standard

Lewis writes that if moral laws are created by the highest power in the universe, this puts humanity in a terrifying position. Since moral laws are often broken, we have reason to believe that the highest power in the universe dislikes our actions. Lewis argues that you ought to be worried—even afraid. However, this worry should inspire you not to hide from God and moral laws, but rather to try to align your conduct with these moral laws. Your best response to this fear lies in finding the courage to commit yourself to a more virtuous life.

Lewis considers this no easy task. If God's moral laws are truly objective then they permit little leniency and few exceptions. Since you have no control over what is right and wrong, you can't decide to exempt yourself from...

Mere Christianity Summary Part 5: The Example of Christ

Lewis argues that Christian faith requires not simply surrendering to God's moral laws, but following a perfect example. Lewis writes that only Christ is capable of setting this perfect example of surrender because he is both human and divine. In this section, we'll explore Lewis’s arguments for Christ’s divinity, why Christ’s dual nature allows him to set the example of perfect surrender, and how Christian practice helps us to become more Christlike.

Christ’s Divinity

Before discussing how Christ's dual nature leads to a perfect example, Lewis lays a foundational argument for the divinity of Christ to help skeptics accept Christ's dual nature. He argues for Christ’s divinity with the following line of reasoning: Christ did not claim simply to be a moral teacher. He claimed to be the son of God, and that he had the power to forgive others' sins. Lewis asserts that Christ’s claim to divinity forces you to accept one of three conclusions:

• Conclusion #1: Christ was lying.
• Conclusion #2: Christ was completely insane.
• Conclusion #3: Christ was God as he claims to be.

Lewis argues that it is unlikely that Christ was either lying or insane. He cites the...

Shortform Exercise: Reflect On Virtue

Lewis argues that virtue will change you. As you make a practice of virtuous acts, you will gradually become more aware of opportunities for virtue, and you will confront all of your vices. This exercise provides a chance to reflect on virtue and opportunities for moral decision-making in your daily life.

Lewis argues that humility is the most important virtue. Only when we are truly humble will we be able to surrender to God's moral laws. Do you agree? If so, explain why. If not, write down which of Lewis’s other key Christian virtues (faith, benevolence, moderation) you consider to be the most important to living a fulfilling life and explain why.

Shortform Exercise: Reflect on the Nature of God

Lewis makes several claims on the nature and character of God. In this exercise, you'll have a chance to reflect on his arguments and develop your perception of God.

Lewis contrasts three potential understandings of God: (1) Christianity’s moral God who has granted us free will, (2) dualism’s moral God who is at war with an evil God, and (3) pantheism’s morally neutral God. Do you share Lewis's perception that the first one is the most compelling? If so, explain why. If not, pick the model you find more compelling and explain why.